A bin bag on my back … volunteers with the Summit Foundation tidy up a Swiss slope. Photograph: Summit Foundation

On a summer hike in certain alpine ski resorts, it’s a sad fact that you’re more likely to spot cigarette butts and discarded drink cans than marmots and ibex. And the evolving nature of that rubbish – discarded by skiers and uncovered when the snow melts in summer – brings new problems for those attempting to clean it up.

“Cans of Red Bull are found fairly often now, whereas they used to be rare,” says Olivier Kressmann, project manager for Summit Foundation, a non-profit organisation promoting environmental awareness in Switzerland. “And these days, paper tissues are more and more resistant, so the life-span of tissues on the pistes is increasing. That’s a new problem over the past two or three years.”

Plastic bottles, chewing gum and lost bits of kit are among the other items proving a headache for resorts, a pollutant of the environment and a turn-off for summer tourists. So, in a bid to raise awareness of the problem, and clean up the slopes, an increasing number of resorts are appealing to skiers and winter hikers to return in summer to help pick up litter on a “mountain-cleaning day”.

“Everyone who goes skiing in winter is our target for the cleaning days,” says Kressmann. “When we use the mountain, we all have responsibility for the rubbish that’s left there.”

Initiated by Summit Foundation in 2001, Switzerland’s cleaning days are nothing new, but they’ve gathered momentum in recent years, with the number of events increasing from around 20 in 2009, when the organisation launched a national campaign, to an expected 50 this year, including Grindelwald-First (11 July), the Schilthorn (29-30 August) and Bettmeralp (12 September).

Volunteers with the litter collected on a clean-up day – 5kg of rubbish is the average harvest per cleaner. Photograph: Summit Foundation

Usually organised by tourist offices and ski-lift operators, the most successful are those held on weekends during peak summer season, capitalising on Switzerland’s popularity with hikers and mountain-bikers to boost turnout. With some events attracting up to 200 people, and each volunteer collecting around 5kg of rubbish, organisers can be left with a genuine ton of rubbish to sort, recycle and dispose of.

And public piste-cleaning isn’t limited to Switzerland. For the seventh year, Dutch company Respect the Mountains is arranging litter-picking days across Europe, including Mayrhofen in Austria (14 July), while French non-profit group Mountain Riders co-ordinates similar events in the French mountains, with Saint-Lary-Soulan in the Pyrenees (19 July) and Val d’Isère in Savoie (9 August) still to come this summer. Last year, around 7,300 volunteers collected 93 tons of rubbish during Mountain Riders’ 110 cleaning days.

A cleaning day is intended to be sociable, fun and family friendly. Volunteers are usually offered perks such as a picnic lunch, barbecue or aperitif to end the day. “You spend a nice day outside, you do something useful and you see a different side of a resort, even one you know well,” says Kressmann. In return, you get the chance to give something back to the mountains that isn’t a can of Red Bull.